You can multiply your square feet number by 1/3 ft (the same as 4 inches) to convert to cubic feet. Then you can divide by 27 cubic ft/cubic yard to convert to cubic yards.
After that, you need to talk to your material supplier to find out how many cubic yards it takes to make a ton, or how many tons per cubic yard--depending on what it is and how they measure it. After you have that density number you can convert your volume to tons.
After that, you need to talk to your material supplier to find out how many cubic yards it takes to make a ton, or how many tons per cubic yard--depending on what it is and how they measure it. After you have that density number you can convert your volume to tons.